Color photography



Sept. 13, 1932.

COLOR PHOTOGRAPHY Filed May 22, 1930 J. N. GOLDSMITH: v 1,877,658

RED GREEN \HQLET I Patented Sept. 13, 1932 UNITED STATES PATENT or-rlcr.

JOHN NAISH eotnsmrrn, or LONDON, E GLAND, ASSIGNOR 'ro srIcEns LIMITED, '01? LONDON, ENGLAND, A BRITISH ooMrANY 1 r COLOR PHOTOGRAPHY Application filed Kay 22, 1930, Serial No. 454,833, and in Great Britain Kay 80, 1929.

This invention comprises improvements in or relating to color photo raphy, and re lates especially to methods or the application of a multicolorscreen to a film compris- 0 ing celluloid, or a cellulose ester, such for example as cellulose acetate or nitro-cellulose. These films are herein referred to collectively as cellulose ester base films, The instant process is applicable in those processes of the type in which there is applied to the surface of the film at one or more stages of the process a series of lines or other geometrical patterns of a greasy resist-material, i; e. a material capable of protecting the underlying portions of the film from solutions of dyes or bleaching agents. Thus, for example, oily resists may be employed to protect the film from aqueous or aqueous alcoholic dye solutions.

One example of a process of this general type is given in British PatentNo. 322,432, according to which the film dyed uniformly with one color (say green) is led through a printing machine by means of which extremely fine parallel lines of greasy ink (in-' tended to act subsequently as fatty resists) are printed upon it. The printing is eflected by means of a small engraved. steel, roller having, for example, fifteen lines and fifteen intervening grooves per millimeter. When the ink is dry the film is passed into contact with a bath which bleaches and dissolves Cal out the green dy'e from the spaces between the lines, leaving unattacked the green lines protected by the ink. Thereafter the film has applied to it another dye, say a red dye, which colors only the spaces between the ink lines, and so forth.

It is one object of the present invention to provide means whereby, in processes of the above described type, the steps of covering the whole surface of the film with one dye, and subsequently bleaching the dye from the inter-spaces between the first series of the resist pattern, may be avoided. In effect when the film has received the lines of resist-medium embodyin r one dye and when the .film has becn suita 1y dried, it may be immediately treated with the next color to produce colored lines between the first mentioned lines.

According to the invention in a method of the type described for applying a multicolor screen for color photography to a film co1nprising celluloid, or a cellulose ester, the resist-medium employed to print one or more ofthe series of lines or other geometrical patternupon the film, contains a dye which penetrates from the medium into the film, so that on removal of the medium, for example by washing with a solvent, a geometrical pattern in color remains on the film.

In the drawing, Fig. 1 shows a film coated with a dye containing resis Fig. 2 shows the film after dyeing between the lines of resist and removing the resist.

Figs. 3 and 4 show a three color variation.

According to a feature of the invention, the dye-bearing medium may comprise a fatty or greasy ink, which is printed on the film ina series of lines, so that after removal of the ink (by washing with benzene) a series of colored lines remains on the film.

The dye-bearing medium may' comprise aresist, a dye miscible with or soluble in said resist and an agent (such as acetic acid) which is a solvent for the dye and enables tih-e dye to penetrate into the surface of the 1 1111.

The dye-bearing medium may alternatively comprise a resist consisting of thickened linseed oil or like thickened vegetable oil, an

oil-soluble dye such as oil orange or oil red, and acetic acid. Any of the dyes in the groups known as oil orange and oil red maybe employed, for instance, those defined under these headings in the color index of the Society of Dyers and Colorists, edited by F. M. Rowey, published in 1924 and suplines in alternate colors is then left on. the

plemented in 1928, and the difference between the s ectral absorptions of the various dyes may be compensated for where necessary in the manner known to those skilled in the art. The specific color value of the dye used is thus of no great importance, it being desirable, however, that the dyes selected should be soluble in oil and insoluble in water.

According to a particular form of this invention, after lines of a resist-material embodying a dyestuif have been printed on the film, a dyestufi' of a different color is applied to those portions of the film which are unprotected by the resist-lines so that after re-- moval of the resist-lines a series of parallel The invention will now be described with reference to the accompanying drawing, which, it is to be understood, is diagram matic only. l

Thesurface of a cellulose ester film is first covered witha series ofparallel lines a; of

a resist material containing dye, see Fig. 1.

An example of a suitable resist material is as follows:

Grams Oil red 20 Thickened linseed oil 2O Acetic acid 20 The surface of the film is then submitted to the action of a green dye bath, e. g. malachite green. The dye will only affect the'portions of the film b which are unprotected by the resist lines. The red dye contained in the resist material will, however, penetrate from the resist into the underlying portions of the film, so that on removing the resists the film will be found to be dyed in a series of parallel green and red bands 0' and d as illustrated in Fig. 2.

If it is desired to obtain a three color screen on the film, a second series of resist lines a which, however, contains no dye, is ruled on the film at right angles to the first series of lines, as shown in Fig. 3. The color is then bleached from the portions of the film between the resist lines, and these portions are then dyed violet.

On removing the resists, a three color screen is obtained comprising, as shown in Figure 4, a series of parallel violet lines sepaon the film, contains a dye which penetrates ester film, the step comprlsmg applying to into the medium of the film, so that on removal of the medium a geometrical pattern in color remains on the film.

2. A method according to claim 1 whereink a series of colored lines remains on the 3. A method according to claim 1 wherein the dye-bearing mediumcomprises a resist,

a dye miscible with or soluble in said resist and an agent which is a solvent for the dye and, enables the dye vto penetrate into the surface of the film.

4. A method according to claim 1 wherein the dye-bearingmedium comprises aaresist consisting of thickened vegetable oil, an oilsoluble dye selected from the groups consisting of oil orange and oil red acetic acid.

5. A method according to claim 1 wherein the dye-bearing medium comprises a. fatty or greasy ink, which is printed on the film in a series of lines, so that after removal of the ink by washing with benzene, a series" of colored lines remains on the dyes and 6. A method according to claim" l 'wherein the dye-bearing medium comprises a resist, a dye miscible with or soluble in said resist and acetic acid.

7. A method of the type described for applying a multi-color screen for color photog raphy to a film containing a cellulose ester, wherein the resist-medium employed to print one or more series of lines or other geometrical patterns on the film, contains a dye which penetrates from the medium into the film, so that on removal of the medium a geometrical pattern in color remains on the film, and wherein after lines of a resist-material embodying a dyestufi have been printed on the film, a dye-stuff of a different color is applied to those portions of the film which are removing said resist medium, leaving said.

dye on said film.

9. In a process of the nature described of applying a multi-color screen to a cellulose ester film, the step comprising printing on said film in at least one series of lines a resist-mediumcontaining a fatty or greasy ink and dye and subsequently removing said resist medium, leaving said dye on said film.

10. In a process of the nature described of applying a multi-color screen to a cellulose said film a resist-medium composed of a resist, a dye miscible with said resist and a mutual solvent for said dye and said film,

. whereby said dye aided'by said solvent penetrates into said film.

11'. The method according to claim 8 wherein the resist-medium is composed of a thickened ve etable -oil, an oil-soluble dye and a solvent or said dye.

12. The method according to claim 8 where- 'in the resistmedium is composed of thickened linseed oil, an oil-soluble dye and a solvent for said dye.

13. The method accordin to claim 8 whereinthe resist-medium is cdinposed of thickened linseed oil, an oil-soluble dye and acetic. acid.

14. A process of applying a multi-color screen to a cellulose ester film adapted for color photography comprising printing on said film at least one series of lines of a resist-medium containing a dye miscible therewith and capable of enetrating the film, applying a dyestufi or a different color to those portions of the film not protected by the resist lines and removing the resist lines, whereby a film is produced containing a geometrical design of alternate series of lines of dyes of different colors.

15. The process according to claim 14 wherein the resist-medium is a fatty or greasy ink having a dye dissolved therein.

16. The process according to claim 14 wherein the resist-medium is a fatty or greasy ink containing an oil soluble dye and acetic acid.

17. A process of applying a multi-color screen to a cellulose ester film adapted for color photography comprising, printing on said film a series of lines of a thickened linseed oil resist containing acetic acid and an oil dye selected from the groups consisting of oil red and oil orange dyes, drying said resist, applyinga dyestuff of a different color to those portions of the film which are unprotected by the resist lines, and removing the resist lines by dissolving the same with benzene, whereby there remains alternate lines of different colors, the dye in said resist having penetrated into the film;

18. A method of the type described for applying a multi-color screen for color photography to a cellulose ester base film wherein the resist-medium employed to print one or more series of lines or other geometrical patterns on the film, contains a dye which pen-1 etrates from the medium into the film, so that on removal of the mediumby washin with a solvent a geometrical pattern in co or re- .mains on the film.-

19. A method of the type described for applying a multi-color screen for color photography to a film containing a cellulose ester, wherein the resist-medium employed to print; one or more series of lines or other: geometr-i cal patterns on the film, oontainsadye which penetrates from the medium into'the film, so that on removal of the medium by washing 

